Search results for "Exponential growth"
showing 10 items of 52 documents
Codimension growth of central polynomials of Lie algebras
2019
Abstract Let L be a finite-dimensional simple Lie algebra over an algebraically closed field of characteristic zero and let I be the T-ideal of polynomial identities of the adjoint representation of L. We prove that the number of multilinear central polynomials in n variables, linearly independent modulo I, grows exponentially like ( dim L ) n {(\dim L)^{n}} .
The kinetic behavior of insulin fibrillation is determined by heterogeneous nucleation pathways
2005
When subjected to acidic conditions and high temperature, insulin is known to produce fibrils that display the common properties of disease amyloids. Thus, clarifying the mechanisms of insulin fibrillation can help the general understanding of amyloidal aggregation. Insulin fibrillation exhibits a very sharp time dependence, with a pronounced lag phase and subsequent explosive growth of amyloidal aggregates. Here we show that the initial stages of this process can be well described by exponential growth of the fibrillated proteins. This indicates that the process is mainly controlled by a secondary nucleation pathway.
Memory effects and coverage dependence of surface diffusion in a model adsorption system
1999
We study the coverage dependence of surface diffusion coefficients for a strongly interacting adsorption system O/W(110) via Monte Carlo simulations of a lattice-gas model. In particular, we consider the nature and emergence of memory effects as contained in the corresponding correlation factors in tracer and collective diffusion. We show that memory effects can be very pronounced deep inside the ordered phases and in regions close to first and second order phase transition boundaries. Particular attention is paid to the details of the time dependence of memory effects. The memory effect in tracer diffusion is found to decay following a power law after an initial transient period. This beha…
Meaning and magnitude of the reduced density matrix cumulants
2012
Abstract Within the framework of a generalized normal ordering (GNO), invented by Mukherjee [1] , the reduced density matrix cumulants of the (multiconfigurational) reference wave function play a central role, as they arise directly from the contraction rules. The extended Wick theorem allows contractions of an arbitrary number of active annihilators and creators through a cumulant of corresponding rank. Because the cumulant rank truncates naturally only at the number of active spin orbitals, practical applications of the GNO concept seem to rely on a fast convergence of the cumulant series, allowing one to neglect cumulants with high rank. By computing cumulant norms for selected systems (…
Exponential growth phase cells of the osmotolerant yeast Debaryomyces hansenii are extremely resistant to dehydration stress
2001
Abstract The osmotolerant yeast Debaryomyces hansenii is highly resistant to dehydration stress and this tolerance was more pronounced for cells taken from the exponential growth phase than from the stationary phase. Growth of D. hansenii in medium containing 10% (w v −1 ) NaCl, resulted in an additional increase in cellular resistance to dehydration, which was most marked for stationary phase cells. It is expected that further investigations of the mechanisms behind this exceptional dehydrational tolerance will reveal new approaches for improvement of the quality of dry yeast.
Mapreduce in computational biology - A synopsis
2017
In the past 20 years, the Life Sciences have witnessed a paradigm shift in the way research is performed. Indeed, the computational part of biological and clinical studies has become central or is becoming so. Correspondingly, the amount of data that one needs to process, compare and analyze, has experienced an exponential growth. As a consequence, High Performance Computing (HPC, for short) is being used intensively, in particular in terms of multi-core architectures. However, recently and thanks to the advances in the processing of other scientific and commercial data, Distributed Computing is also being considered for Bioinformatics applications. In particular, the MapReduce paradigm, to…
Enchytraeid population dynamics: Resource limitation and size-dependent mortality
2009
Abstract Enchytraeids are regarded as keystone soil organisms in forest ecosystems. Their abundance and biomass fluctuate widely. Predicting the consequences of anthropogenic disturbances requires an understanding of the mechanisms underlying enchytraeid population dynamics. Here I develop a simple model, which predicts that the type of dynamics is controlled by resource input rate. If fungal resource input is a discrete event once a year, an exponential growth phase is followed by starvation and sharp decline of enchytraeid abundance. Model simulations with three different forcing functions were compared to field data. Initial parameter values were obtained from various independent sources…
Degrees of irreducible characters of the symmetric group and exponential growth
2015
We consider sequences of degrees of ordinary irreducible S n S_n - characters. We assume that the corresponding Young diagrams have rows and columns bounded by some linear function of n n with leading coefficient less than one. We show that any such sequence has at least exponential growth and we compute an explicit bound.
On the exponential growth of graded Capelli polynomials
2013
In a free superalgebra over a field of characteristic zero we consider the graded Capelli polynomials Cap M+1[Y,X] and Cap L+1[Z,X] alternating on M+1 even variables and L+1 odd variables, respectively. Here we compute the superexponent of the variety of superalgebras determinated by Cap M+1[Y,X] and Cap L+1[Z,X]. An essential tool in our computation is the generalized-six-square theorem proved in [3].
Growth phase-dependent regulation of nuoA-N expression in Escherichia coli K-12 by the Fis protein: upstream binding sites and bioenergetic significa…
2000
The expression of the nuoA-N operon of Escherichia coli K-12, which encodes the proton-pumping NADH dehydrogenase I is modulated by growth phase-dependent regulation. Under respiratory growth conditions, expression was stimulated in early exponential, and to a lesser extent in late exponential and stationary growth phases. The stimulation in the early exponential growth phase was not observed in fis mutants, which are deficient for the growth phase-responsive regulator Fis. Neither the alternative sigma factor RpoS nor the integration host factor (IHF) are involved in growth phase-dependent regulation of this operon. When incubated with nuo promoter DNA, isolated Fis protein formed three re…